1. Field of the Invention
This invention relates to a gas generator, and, more particularly, to a gas generator for the gasification of finely-grained solid fuel. This invention is especially useful for the volatilization and carbonization of coal present in a fluidized bed.
2. Decription of the Prior Art
Conventional heat exchangers for this purpose have been densely distributed in a vertical and horizontal arrangement in order to supply a constant amount of heat to all parts of large-scale technological gas generators. However, the prior art incompletely utilized the constant supply of heat. The reason for this incomplete utilization is connected with the accumulation of free hydrogen in areas proximate to the vertically arranged parts of the heat exchangers. It has been experimentally determined that the speed of gasification is inversely proportionate to the partial pressure of hydrogen. Therefore, less heat of reaction is necessary in areas where free hydrogen has accumulated.
The gas generators of large-scale technology have a feeding end on one side, and a waste removal end on the other side. Less heat of reaction is required per unit volume of the horizontal fluidized bed as it progressively approaches the ash discharge outlet.
Two basic disadvantages of conventional apparatuses are the results of their structure. First, heat transfer per unit area of the heat exchanger is reduced in a vertical and horizontal direction. Second, the reduction in heat transfer leads to a higher temperature in both the vertical and horizontal directions. This temperature increase means that there is a disproportionate burden on the heat exchangers.